Some Toshiba laptops have the transflective LCD and toshset
can control its backlight state.  I brought this feature to the
mainline.  To support transflective LCD, it's implemented by
adding an extra level to the backlight and having 0 change to
transflective mode.  It was tested on a Toshiba Portege R500.

Signed-off-by: Akio Idehara <[email protected]>
---
 drivers/platform/x86/toshiba_acpi.c |   59 ++++++++++++++++++++++++++++++++--
 1 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/toshiba_acpi.c 
b/drivers/platform/x86/toshiba_acpi.c
index eef3b53..f4188b0 100644
--- a/drivers/platform/x86/toshiba_acpi.c
+++ b/drivers/platform/x86/toshiba_acpi.c
@@ -95,6 +95,7 @@ MODULE_LICENSE("GPL");
 
 /* registers */
 #define HCI_FAN                                0x0004
+#define HCI_TR_BACKLIGHT               0x0005
 #define HCI_SYSTEM_EVENT               0x0016
 #define HCI_VIDEO_OUT                  0x001c
 #define HCI_HOTKEY_EVENT               0x001e
@@ -134,6 +135,7 @@ struct toshiba_acpi_dev {
        unsigned int system_event_supported:1;
        unsigned int ntfy_supported:1;
        unsigned int info_supported:1;
+       unsigned int tr_backlight_supported:1;
 
        struct mutex mutex;
 };
@@ -478,6 +480,22 @@ static const struct rfkill_ops toshiba_rfk_ops = {
        .poll = bt_rfkill_poll,
 };
 
+static int get_tr_backlight_status(struct toshiba_acpi_dev *dev, u32 *status)
+{
+       u32 hci_result;
+
+       hci_read1(dev, HCI_TR_BACKLIGHT, status, &hci_result);
+       return hci_result == HCI_SUCCESS ? 0 : -EIO;
+}
+
+static int set_tr_backlight_status(struct toshiba_acpi_dev *dev, int value)
+{
+       u32 hci_result;
+
+       hci_write1(dev, HCI_TR_BACKLIGHT, value, &hci_result);
+       return hci_result == HCI_SUCCESS ? 0 : -EIO;
+}
+
 static struct proc_dir_entry *toshiba_proc_dir /*= 0*/ ;
 
 static int get_lcd(struct backlight_device *bd)
@@ -485,10 +503,22 @@ static int get_lcd(struct backlight_device *bd)
        struct toshiba_acpi_dev *dev = bl_get_data(bd);
        u32 hci_result;
        u32 value;
+       int tmp = 0;
+
+       if (dev->tr_backlight_supported) {
+               if (!get_tr_backlight_status(dev, &value)) {
+                       if (value)
+                               tmp = 1;
+                       else
+                               return tmp;
+               } else {
+                       return -EIO;
+               }
+       }
 
        hci_read1(dev, HCI_LCD_BRIGHTNESS, &value, &hci_result);
        if (hci_result == HCI_SUCCESS)
-               return (value >> HCI_LCD_BRIGHTNESS_SHIFT);
+               return (value >> HCI_LCD_BRIGHTNESS_SHIFT) + tmp;
 
        return -EIO;
 }
@@ -497,15 +527,18 @@ static int lcd_proc_show(struct seq_file *m, void *v)
 {
        struct toshiba_acpi_dev *dev = m->private;
        int value;
+       int levels = HCI_LCD_BRIGHTNESS_LEVELS;
 
        if (!dev->backlight_dev)
                return -ENODEV;
 
+       if (dev->tr_backlight_supported)
+               levels++;
+
        value = get_lcd(dev->backlight_dev);
        if (value >= 0) {
                seq_printf(m, "brightness:              %d\n", value);
-               seq_printf(m, "brightness_levels:       %d\n",
-                            HCI_LCD_BRIGHTNESS_LEVELS);
+               seq_printf(m, "brightness_levels:       %d\n", levels);
                return 0;
        }
 
@@ -521,6 +554,13 @@ static int lcd_proc_open(struct inode *inode, struct file 
*file)
 static int set_lcd(struct toshiba_acpi_dev *dev, int value)
 {
        u32 hci_result;
+       if (dev->tr_backlight_supported) {
+               int ret = set_tr_backlight_status(dev, !!value);
+               if (ret)
+                       return ret;
+               if (value)
+                       value--;
+       }
 
        value = value << HCI_LCD_BRIGHTNESS_SHIFT;
        hci_write1(dev, HCI_LCD_BRIGHTNESS, value, &hci_result);
@@ -541,6 +581,10 @@ static ssize_t lcd_proc_write(struct file *file, const 
char __user *buf,
        size_t len;
        int value;
        int ret;
+       int levels = HCI_LCD_BRIGHTNESS_LEVELS;
+
+       if (dev->tr_backlight_supported)
+               levels++;
 
        len = min(count, sizeof(cmd) - 1);
        if (copy_from_user(cmd, buf, len))
@@ -548,7 +592,7 @@ static ssize_t lcd_proc_write(struct file *file, const char 
__user *buf,
        cmd[len] = '\0';
 
        if (sscanf(cmd, " brightness : %i", &value) == 1 &&
-           value >= 0 && value < HCI_LCD_BRIGHTNESS_LEVELS) {
+           value >= 0 && value < levels) {
                ret = set_lcd(dev, value);
                if (ret == 0)
                        ret = count;
@@ -1104,8 +1148,15 @@ static int __devinit toshiba_acpi_add(struct acpi_device 
*acpi_dev)
 
        mutex_init(&dev->mutex);
 
+       /* Determine whether or not BIOS supports transflective backlight */
+       ret = get_tr_backlight_status(dev, &dummy) ? false : true;
+       dev->tr_backlight_supported = ret;
+
        props.type = BACKLIGHT_PLATFORM;
        props.max_brightness = HCI_LCD_BRIGHTNESS_LEVELS - 1;
+       /* adding an extra level and having 0 change to transflective mode */
+       if (dev->tr_backlight_supported)
+               props.max_brightness++;
        dev->backlight_dev = backlight_device_register("toshiba",
                                                       &acpi_dev->dev,
                                                       dev,
-- 
1.7.7.6

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